• Microbiology and Biotechnology Letters
• /
• v.18 no.4
• /
• pp.394-400
• /
• 1990

Maximization of productivity of recombinant cell fermentations requires consideration of the inverse relationship between the host cell growth rate and product formation rate. The problem of maximizing a weighted performance index was solved by using optimal control theory for recombinant E. coli fermentation. Concentration of a growth inhibitor was used as a control variable to manipulate the specific growth rate, and consequently the cloned-gene expression rate. Using a simple unstructured model to describe the main characteristics of this system, theoretical analysis showed that the optimal control profile results in an initial high growth rate phase followed by a low growth rate and high product formation rate phase. Numerical calculations were done to determine optimal switching times from the growth to the production stage for two representative cases corresponding to different dependency of the product formation rate on the growth rate. For the case when product formation rate is sensitive to the specific growth rate, the optimized operation yields about 60% increase in the final product concentration compared with a simple batch fermentation.

• Journal of Engineering Education Research
• /
• v.23 no.5
• /
• pp.26-39
• /
• 2020

The purpose of this study was to compare and analyze the employment rate of engineering graduates in the last eight years (2011-2018) by gender and majors. Using the statistical yearbook for employment of higher education graduates provided by the Korea Educational Development Institute (KEDI), the employment rate and retained employment rate of engineering graduates were investigated. As results, first, the employment rate has been decreasing since 2011, and the gender employment rate gap has not narrowed and women have always been lower than men. Second, most of the engineering graduates were workers with employee health insurance. On the other hand, women were higher than men in works with self-employee health insurance. Third, from 2016 to 2018, the retained employment rate of engineering graduates was similar, and as the survey progressed, the retained employment rate decreased. In particular, women had lower retained employment rate than men. The study is meaningful in that it suggested ways to bridge the gap between gender and majors employment rates of engineering graduates.

• Journal of People, Plants, and Environment
• /
• v.22 no.2
• /
• pp.219-229
• /
• 2019

This study was carried out to verify the accuracy of fitness tracking devices in monitoring heart rate and energy consumption and to contribute to the development of a forest exercise program that can recommend the intensity and amount of forest exercises based on personal health-related data and provide monitoring and feedback on forest exercises. Among several commercially available wearable devices, Fitbit was selected for the research, as it provides Open API and data collected by Fitbit can be utilized by third parties to develop programs. Fitbit provides users with various information collected during forest exercises including exercise time and distance, heart rate, energy consumption, as well as the altitude and slope of forests collected by GPS. However, in order to verify the usability of the heart rate and energy consumption data collected by Fitbit in forest, the accuracy of heart rate and energy consumption were verified by comparing the data collected by Fitbit and reference. In this study, 13 middle-aged women were participated, and it was found that the heart rate measured by Fitbit showed a very low error rate and high correlation with that measured by the reference. The energy consumption measured by Fitbit was not significantly different from that measured in the reference, but the error rate was slightly higher. However, there was high correlation between the results measured by Fibit and the reference, therefore, it can be concluded that Fitbit can be utilized in developing actual forest exercise programs.

• Journal of the Korean Society for Railway
• /
• v.7 no.1
• /
• pp.55-59
• /
• 2004

Composite materials were used widely due to merit of light weight, low maintenance cost and easy installation. But it is the cause of enormous casualties to men and properties because of weak about the fire. Particularly, it is more serious in case of subway train installed composite materials. For this reason, experimental comparison has been done fur measuring heat release rate(H.R.R) and smoke production rate(S.P.R) of interior panels of electric motor car using cone calorimeter. A high radiative heat flux of 50kW/㎡ was used to bum out all materials and to simulate the condition of fully developed fire case in the tests. It was observed that Heat Release Rate and Smoke Production Rate curves were dependent on the kinds of the interior materials. From the heat release rate curves, the sustained ignition time, peak heat release rate and total heat release rate were deduced, These data are useful in classifying the materials by calculating two parameters describing the possibility to flashover.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 1999.03a
• /
• pp.243-248
• /
• 1999

There is substantial evidence that anatomical connections and functional interactions exist between vestibular and autonomic systems. Heart rate variability (HRV) including mean, standard deviation, coefficient of variation (CV), power spectrum was analyzed for evaluation of the physiological role of the vestibular system on control of heart rate in rabbits. In anesthetized rabbits, electrical stimulation of the vagus nerve decreased heart rate and decreased LF/HF by increasing HF. On the cervical sympathetic nerve increased heart rate and increased LF/HF by increasing LF. Atropine, cholinergic blocker, increased heart rate and increased LF/HF by reducing HF, and propranolol, ${\beta}$-adrenergic blocker, decreased heart rate and decreased LF/HF by reducing LF> In unanesthetized rabbits, stimulation of the vestibular system induced by rotation or caloric increased heart rate and increased LF/HF by increasing LF> Also electrical stimulation of the vestibular nerve produced the same of effects as rotation or caloric in anesthetized rabbits. These results suggest that Stimulation of the vestibular system increased heart rate not by inhibiting the parasympathetic nerve but by activating the sympathetic nerve.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.8
• /
• pp.245-249
• /
• 2013

In this paper, we propose two rate control algorithms for multi-view extension of HEVC with two rate control algorithms adopted in HEVC and analyze the multi-view rate control performance. The proposed multi-view rate controls are designed on HEVC-based multi-view video coding (MV-HEVC) platform with consideration of high-level syntax, inter-view prediction, etc. not only for the base view but also for the extended views using the rate control algorithms based on URQ (Unified Rate-Quantization) and R-lambda model adopted in HEVC. The proposed multi-view rate controls also contain view-wise target bit allocation for providing the compatibility to the base view. By allocating the target bitrates for each view, the proposed multi-view rate control based on URQ model achieved about 1.83% of average bitrate accuracy and 1.73dB of average PSNR degradation. In addition, about 2.97% of average bitrate accuracy and 0.31dB of average PSNR degradation are achieved with the proposed multi-view rate control based on R-lambda model.

• Journal of Veterinary Clinics
• /
• v.20 no.1
• /
• pp.121-130
• /
• 2003

The purpose of this study was to investigate the effect of breeding conditions on reproductive efficiency of thoroughbred broodmares by ultrasonography. The mean age and breeding career of 120 mares used in this study were 11 years old and 6 years, respectively. The average pregnancy rate and embryonic loss rate were 87.5%, 11.8%. The groups that were 8-10 years old, 4-6 years, maiden and mated on May showed the highest pregnancy rate. While mares mated on 1st estrus post partus had the highest ovulation rate but showed the highest embryonic loss rate and he lowest pregnancy rate. And broodmares that had more intrauterine foreign bodies such as cyst and fluid with age and breeding career had represented lower pregnancy rate and higher embryonic loss rate than those having normal uterine condition. These results suggest that the breeding condition and uterine environment of mares had a significant influence on reproductive efficiency.

• Journal of Information Technology Applications and Management
• /
• v.29 no.2
• /
• pp.39-50
• /
• 2022

This research confirmed whether banks and saving banks increase their deposit margin under changes in the base rate. This paper has conclusions as follows. First, when the Bank of Korea changes the base rate, deposit rate variable are significant with panel analysis in the total data set and saving banks. This result implies that changes in the base rate affect deposit margin. Second, this study confirmed whether banks and saving banks maximize their deposit margin as base rate changes. As a result, when the Bank of Korea cut the base rate, the deposit margins of banks and saving banks decreased significantly. Still, their deposit margins are not statistically significant in the opposite situation. Therefore, this paper could not find evidence that banks and saving banks behave to maximize their deposit margin. Maybe, this phenomenon can appear because these financial institutions recognize this criticism.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.5
• /
• pp.380-388
• /
• 2019

Jet engine modulation(JEM) signals are widely used for target recognition. These signals coming from a potentially hostile aircraft provide specific information about the jet engine. In order to obtain the number of blades, which is uniquely provided by the JEM signal, one must extract the spool rate, which is the rotation speed of the blades. In this paper, we propose an algorithm to extract the spool rate from a weak JEM signal. A criterion is developed to extract the spool rate from the JEM signal by analyzing the intensity of the JEM signal component. The weak signal is first subjected to a high-pass filtering-based process, which modifies it to facilitate spool rate extraction. We then apply a peak detection process and extract the spool rate. The technique is simpler than the existing CEMD or WD method, is accurate, and greatly reduces the time required.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.16 no.1
• /
• pp.36-41
• /
• 2013

In this paper time series wave data are simulated using wave spectrum with random phases of the wave signal. The simulated wave signals are used to study the effect of the sampling rate on the ocean wave characteristics. Effect of sampling rate on wave data which include extreme wave such as freak waves are examined and various wave characteristics including abnormality index (AI), kurtosis of wave profile and maximum wave height are examined. Various wave heights are decreased as the sampling rate decreases. The zero-th moment of the wave spectrum does not affect much on the sampling rate but the second moment are greately affected on the sampling rate. The error due to the sampling rate is decreases as the wave period increases. The error in significant wave height based on the wave spectrum $H_s$ is smaller than that on the time domain method $H_{1/3}$. AI index and kurtosis of wave profile do not deviate much from the exact date as long as the sampling rate is greater than 1 Hz. Ocean wave measurement with the sampling frequency higher than 1 Hz will result the error less than 5% in estimating the height of extreme waves.